Naming of source files:
The name of a LATEX source file should be one word (no spaces, no special characters), and end with .tex.
(for example, myfile.tex)
Spacing in text and math:
Many spaces equal one space in text, whereas your spacing is ignored in math, unless the space terminates a command.
Use the align environment.
Separate the lines with \.
In each line, indicate the alignment point with &, one & per line.If the alignment point is adjacent to an =, +, and so on, place it before to ensure proper spacing.
Place a \notag command in each line that you do not wish numbered. If no line should be numbered, use the align* environment.
Place a \label command in each numbered line you may want to reference with \ref, \eqref, or \pageref.
LaTeX is a comprehensive set of markup commands used with the powerful typesetting program TeX (developed by Donald E. Knuth) for the preparation of a wide variety of documents. Researchers, educators, and students in universities, as well as scientists in industry, use LaTeX to produce professionally formatted papers, proposals, and books. LaTeX (developed by Leslie Lamport) is an open source software system, available for download free of charge under LPPL. LaTeX is not a word processor! Instead, LaTeX encourages authors not to worry too much about the appearance of their documents, but instead concentrate on getting the right content. The LaTeX core is maintained by the LaTeX3 Project Group but it also benefits from extentions written by hundreds of user/contributors.
Version 2 or LaTeX2e is now the standard version, and LaTeX 2.09 is considered obsolete.
Packages are a very important feature of LaTeX. These are extensions to the basic LaTeX commands that are written to files with names that end in .sty
Five types of packages are: